Combination cut-off and chamfering tool



June 14, 1960 R. E. NOVKOV COMBINATION CUT-OFF AND CHAMFERING TOOL Original Filed June 19, 1956 2 Sheets-Sheet 1 INVENTOR. RAYMOND E. NOVKOV jmimm 3 I ATTORNEY United States Patent 2,940,160 COMBINATION CUT i%F(?I'AND CHAMFERING Raymond E. Novkov, 1016 Seward, Akron, Ohio Original application June 19, 1956, Ser. No. 592,436. Divided and this applicationMay 7, 1958, Ser. No. 733,591 r 9 Claims. (CI. 29-97) This invention relates to the art of machine tools and in particular has reference to an improved type of cutoff or parting tool that efiectuates a combined chamfering and cut-off operation during use thereof.

It has long been known in the prior art that a length of work can be cut or trimmed into a shorter length during the supported rotational movement thereof by the application of a cutting tool against the rotating external surface of the work. in thegreat majority of cases, such cut-off operations are etfectuated by theuse of a lathe with the work being rotatably supported about its axis over the lathe bed while th'ejcut-ofi tool is secured to a cross-slide carriage so as to move transversely of the lathe bed and thus engage the rotating work surface.

To the present time, cut-off tools of known construction have been characterized by their inability to fully attain one or more of the following desired requirements:

First, the cutting edge per se of the cutting tool must be positioned so that the same will move along a radial plane that extends to the center line of the work as defined by its position of mounting on the tail stock or face plate of the lathe. This requirement assures correct contact be tween the cutting edge and revolving work piece.

In instances, the prior arthas failed in this requirement because of the fact that the cutting tool upon being repositioned after removal for sharpening, for example, is not correctly relocated in the carriage tool holder of the cross slide and, accordingly, the cutting surface is not positioned in the required horizontalplane that is above described.

The second requirement of correct cut-off tool construction is that the cut-off bit per se be rigidly and solidly supported at all times during the cut-off operation, so that any detrimental vibration or chatter" is avoided. The quick change requirements of present-day machine tool practice has heretofore limited the amount of support that can be utilized, with the result that conventional cut-oif tools at the present time are almost without exception, possessive of varying degrees of vibrational chatter which, accordingly, limits the efliciency of the cutoff operation.

A third requirement for the theoretically ideal cut-ofi tool is that the tool bit per 'se and the support plate therefor be capable of rapidly dissipating the relatively high temperatures that occur at the point of cut, so as to avoid premature tool damage that occurs as a result of hot chips welding to the cutoff tool upon their removal from the work piece during the cut-off operation.

A third requirement for the theoretically ideal cut-off tool is that the tool bit per se and the support plate therefor be capable of rapidly dissipating the relatively high temperatures that occur at the point of cut, so as to avoid premature tool damage that occurs as a result of hot chips welding to vthe cut-off tool upon their removal from the work piece during the cut-off operation.

In co-pending application, Serial No. 557,785, filed January 6, 1956, by Raymond E. Novkov, there was disclosed an improved type of cut-off tool that met each and Patented June 14, 1960 ice every one of the above requirements and which featured the use of a cutting bit that was disposed ina substantially tangential plane to the path of movementof the work being cut.

In this regard, it is found that the greatest force resisting cutting action was directed tangentially of the rotating work and, accordingly, if the cutting tool wasarranged so as to have its longitudinal length disposed'in this tangential plane, it was found that the same w ould' absorb the cutting force of its longitudinal length. v l

By way of contrast, in devices where the cutting-bit disposed in a radial plane, the cutting point'wi ll bedisposed substantially normal to the direction of force, with the result that the force as received by the blade willtend to bend or flex the same throughout its longitudinal length. v

Thus, by featuring a cut-off tool that is disposed substantially in the line of the cutting force tangential ,to rotating Work, the cutting bit per se is capable of absorbing this force throughout its longitudinal length with the result that improved cutting action will occur in such case.

While the above described type of cut-off tool featuring a tangentially disposed cut-off cutting bit, per so, has been found satisfactory in usage, it has been found that it is desirable in many cases to provide a chamfering operation after the cut-off has been effectuated. In present day practice, this requires a separate set-up and cutting operation, with the result that additional time is consumed "to thus add to the overall cost of the operation being performed. In co-pend-ing application, Serial 505,488, filed May 2, 1955, by Raymond E. Novkov, there'is disclosed an improved type of cut-off tool that is disposedin a radial plane and it has been found that, by providing this type blade for chamfering action in cooperation withthe tangentially disposed cutting bit used in the cut-off operation per so, that the material can be cut off and the remaining stock chamfered at its peripheral edges during the same cutting operation. 7 i V It accordingly becomes'the principal object of this invention to provide animprovetype of cut-01f "m1 teaching the use of ,a tangentially disposed cut-ofi bit ii -combination with a radially disposed chamferin'g bit for effectuating a combined cut-01f and 'chamfering operation.

It is the further object of this iuvention'to provide a cut-off ,tool of the character described'that includes, in combination for co-action with each other, a pair of'cutting bits, one of which performs a cutting operation, while the other performs a chamfering operation automatically upon completion of the cut-off.

It is a still further object of this invention to provide an improved cut-off tool characterized by the presence of two cutting bits operable in co-action with each other and having the spacing therebetween adjustable so that a combined cut-0E and chamfering action can be obtained on revolving pieces of difierent diameters.

It is the still further object of this invention to provide a combination cut-off and chamfering tool of the character described that is eflicient in use and economical to produce. i v

These and other objects of the invention willbecome "more apparent upon a reading ofthe following brief specifications considered and interpreted in the light of the accompanying drawings.'

Of the drawings: I 1 Figure 1 is an exploded perspective View of the improved tool.

Figure 2 is a side elevation of the combination tool being used to effectuate a combined cut-off and'chamfering operation, and showing a chain-dotted line revolving work piece.

Figure 3 is a plan view of the combination cut-off tool during the machining operation.

,Referringnow to the drawingsv and particularly to V lgthreoflfthe improvedfcombination cut-offand chamferingtool, generally indicatedfby the numeral 10, l isfshownincludingatool body 20, tofwhich is'releasably secured-a bitrsuppor'ting member 30 that receives on V appropriate edge portions thereof av cutting bit 40 and a,;chamfering,bi tf45;"tlie arrangement being; such that o clampingblocks 50'and'60 arerel'e'asably secured to the 2'0Eand the member 30-respectively so as to retain i the cham fering bitt45 and thefcutting'bit'40with respect I were member 130, as 'will' presently be described.

Con'sid ering first thefsti'ucture of the tool body'zthiit surface 2 l. of the tool body 20 is undercut adjacent its frontand side marginaledge portions to define a shallow ,7 recess that includes -a supporting surface 23 and a longi- -tudinally extending groove 24 with both. the surface 23 groove 24 being located below the plane of surface ,;21, so-as;to provide-a seat for the complementally shaped clamping block 50. Additionally, the surface 23 includes v aitappedaperture23a that receives a clamping bolt 25 that; IflIIlQtlOlilfi V Vin-known manner to fixIthe clamping block .,-50 with respect to the surface 23 and the .groove 24. t V ;By like token, the side surface 22 of thetool'body 29 is-shown undercutzadjacent its frontedge portion to define arecessed surface 26 that is bounded by wall-surfaces 7 26a, 26b, '26jc'and26d, as well' as the frontal surface 26e ,of,;; the toolbody v20, so as to permit the'bit-supporting member j30 to; have a"flat- .portion thereof receivable agallstthe surface 26 as will be described; I ;In order that the bit-supporting member 30' may be abetted firmly againstv the surface 26,. the :same (surface 26)..fur,therv includesa plurality of tapped apertures 28,

28,: th,e spacing and arrangement of which will be de scribediyingreater' detail in ensuing paragraphs.

' As bestshown in; Figure l of the drawings, the vrear portion of the tool body 20 is provided with a bevelled surface 29'that intersects with-surfaces 21 and 22m assembled condition'as will be described.

Considering, next; the detailed structure of the bitsupportlng member 301361 se,-it will be seen from Figurm 1 to 4 of the drawing that the same includes a shank portion,. indicatedfgenerally bythe numeral30b, that integrallyejoins an enlarged; head portion indicated by --th'e;;numerall 31; with these shank-and head portions 30b, 31 defining a longitudinal. slot- 32 Within which may be received a blade support 33, having a V-shap ed front sa e 33a 3 against which, may. be :received the cutting bit 40, while the chamfering bit is receivedagainst a: Wshaped/groove30a that is'defin'ed by the shank porn t-iomaob;

, As is best shown iniFigure l of the drawings, the shank portion 30b further includes counter-sunk apertures 34,. 34 i "thatnza're anrange'd' for alignment with the apertures 28,

28. In this regard, it is'to'befunders'tood that similar apertures 34b, 34b are provided forwardly in the shank portion" for coactionwiththe-blade support33 that is retained within slot 32 upon tightening of bolts through this second set of apertures 34b, 3417. As is explained in co-pending application, Serial No. 505,488, filed May 2, 1955, by Raymond Novkov, the apertures 28, 28

that are provided in the face -26 of tool body 20 are slightly out: of :alignmentrwith thecounter-sunkrapertures 34, 34, with such purposeful misalignment being providedfor thepurpose of drawing edge portions 31a, 31b,

and 31c of shank7305*intotight abutmentwith/the wall In order that clearance may be provided-foremission of chips cut by the ohamfering bitAS, the front or leading edge of the shank portion30bds shown defined by an angularly disposed surface that is indicated by the numeral 35 with this surface 35 being arcuately formed for clearance with respect tv the revolving work a piece.

, v.Sirhilarl'y, while the cutting bit 40- is supported against the V shaped edge I 33aas aresult' ofpositioning of the clamping block'60 as will-be presentlydescribed, theenlarged head portion 3110111161" includes an, auxiliary support portion 36, having an aperture 36a through which a bolt can be secured so as to secure the portion 36 against the frontal face 20a of-the" tool body 20, with an aperture 19abeingprovided on the face 20a for the purpose of receiving 'a belt that is" passed through the aperture 36a. As before; thisauxili'ary mounting portion 36- includes an arcuate face 39" that provides clearance for the revolving workpiece. r

In addition 'to the aforementioned component parts, the enlarged head portion 311 includes further a frontal face 37 having a tapped aperture-37a and a vertical grooves-37b, both of which; coaetwiththe-clamping block 60,.while tapped aperture 38ai'isprovided on horizontal (Figure. 2) face 38 soas to receiveone axial-end of the cutting bit' 40 so that thesame maybe "abutted against V elongated configuration having'a V-shaped frontal edge 41 thatiscomplementallyreceived within the \.'-shaped edge 33a of bla'de support '33. .Iii the preferredembodr ment of the invention'disclosed'herein, the cutting bit 40. is made upjof two elongated'portions 42 and 43 with the portion 42 being a carbide insert, for example, while the shankor base, portion,43,may be of steeL'if desired.

A threaded integral extension 44', projecting from the shank portion 43,, has' threadingly received :thereon an adjustment nut 44a that, operates tof vertically space and axially locate the cuttingbit 40'al'ongjthe; V=shaped edge 33a as is best shown in Figure 5 of the, drawings. a

The elongated chainfe'rin'g bit 45 is of similar elongated configurationandmay include a shank portion 46 having a -V-shapededge- 47 thereon that is complementallyreceived withintheN-shaped groove 30;: of the shank 31. A head, or chamfering end 48of the chamfering tool 45, is normally formed of carbide material and has an angularly disposed; cutting vface. 49' that overlies the angularly disposed, surface 35 best shown in Fig; 3" of the 7 drawings.

Referring ino w to Figures 1,12 ,v 3' and 4 of the drawings for a, vdetailed;. description, of the V clampingv block 50, per se, it willbe seen, that thesame isjdefined by 7 a. substantiallyyrectangular body section, that includes 1 anintegral; extension arm.,51 thatprojects from the front surface 59a .thereofasoas ,tollongiftudinally; overlie the c-hamfering bit 45 when thefsame is, positioned? against ,the'V-shaped edge, 30a as is. shown in Eiguresl2;3 and 4 of the drawings, In orderr t hat a degreeof cantilever support- 'between the arnr 51 and'the .chamfering bit 45 be provided adjacent, the free end. 5la of, the arm 51,

. thel bottome surface 51b ofv arm,.51;is shown tapered lon- .for the sake of clarity.

what exaggerated condition in Figure 2 of the drawings It is to be understood that a taper in the nature of one or two degrees could be employed without changing the principle herein involved.

In order that this tapered surface 51b of the arm 51 will longitudinally overlie the chamfering bit 45 positioned on groove 30a of member 30, the block 50 further includes a transversely spaced, longitudinally extending flange 52 that descends downwardly from the lower surface 50b of the block 50 to seat in the groove 24 of the tool body 20 upon attachment of block 59 to the body 20 as a result of bolt 25 being passed through aperture 53 in block 50, for reception in aperture 23a, it being understood that this aperture 53 includes a shoulder 53a against which a head of bolt 25 may be positioned so as to draw the clamping block 50 into firm engagement with the chamfering bit 45 upon turning of head 25a thereof in known manner.

With reference now to the construction of the support of the clamping block 60, it will be seen that the same includes a base portion 61 of generally rectangular configuration, which base portion 61 is provided with an aperture 62 that extends between the opposed faces 61a and 61b thereof for purposes to be described.

One edge portion 63 of the base 61, further defines a projecting arm 64 of generally tapering cross-sectional configuration that defines a clamping surface 65 that is inclined slightly with respect to the plane of the surface 61b so as to permit the extreme end 65a thereof to initially contact the surface of the clamping bit 40 as will be presently described. In addition to the aforementioned component parts, the face 610! further includes a transversely extending rib 66 as well as a small projection 67 (see Figure 1) that is designed to engage against the surface 37 with the rib 36 being received in the groove 37b of surface 37 while the projection 67 abuts against the surface 37 at a spaced point therefrom. Bolt 68 passing through aperture 62 for reception in aperture 37a facilitates retention of the block 66 with respect to the bitsupporting member 30, so that upon tightening of the bolt 38, the clamping surface 65 of arm 64 will be tightly urged into contact with the cutting bit 40, with the leading edge 65a thereof first contacting the bit 49.

In use or operation of the improved cut-off tool 10, it will be first assumed that the bit-supporting member 30 has been secured with respect to the tool body 20 as previously described and further that the cutting bit 40 and the chamfering bit 45 have been seated with respect to V-shaped surfaces 33:: and 3011 respectively and are being retained in place thereon as a result of the clamping blocks 50, 60 being positioned in engagement therewith.

At this time, the tool is ready for use in a combination cut-ofl and chamfering operation and to this end the flange portion 19 may first be conveniently positioned in a lathe, for example, and fixedly retained therein in known manner. With such assembly completed and the tool positioned, the overall device 10 will assume the combination shown in Figures 2, 3 and 4 of the drawings and in this condition the same may have the cutting edge 42a of cutting bit 40 advanced into a piece of rotating work R that is indicated in chain-dotted line in Figs. 2 and 3 of the drawings.

In the condition of Figure 2, a cut has been made by a gradually advancing cut-off tool 10 to the left of Figure 2 so that when the condition shown in Figure 2 is reached, the cutoff operation is substantially complete. At this time, it will also be noted that there has been effectuated a chamfering action that results in the creation of a chamfered surface indicated by the chain-dotted line designation 70 in Figures 2 and 3 of thedrawings.

During the movement of the component parts to'the position of Figure 2, it is believed apparent that the cutting edge 42:: of the cutting bit 40 will have effectuated a cut-off operation with the cutting force that is 6 created during such operation being absorbed throughout the longitudinal length of the cutting bit 40 which is seated against a head 31 as clearly shown in the drawings.

Similarly, as a result of the taperedcutting surface 49 contacting the revolving work piece R during movement to the left of Figures 2 and 3, it is apparent that this surface will effectuate a chamfer cut that results in the creation of the aforementioned surface 70. During the time that this chamfering operation is occurring, it is believed apparent that the revolving work piece will clear the surface 35 so as to obviate interference between these arts.

p In the event it is desired to replace either of the cutting bit 40 or the chamfering bit 45, it is merely necessary that the appropriate clamping block 50 or 60, as the case may be, be unloosened as a result of the backing off the retaining screws used thereon. Upon such loosening either the cutting bit 40 or the chamfering bit 45 may be easily removed.

With respect to the adjustment of the positioning of the bit 45 with respect to bit 40, it is believed apparent that the screw 2? will determine the location of the bit 45 with respect to the center line of the work being machined, while the cutting bit 40 may be set to a pre-determined height by merely adjusting the nut 44a upon the threaded shank portion 44 thereof. In this manner, a uniform distance can be maintained between the bottom of the threaded bolt 44a and the cutting surface 4211 with the result that upon pre-setting of this device the same can merely be replaced in the aperture 38 so as to have the cutting edge 42a provided at a proper height X (see Figure 2) above the surface 38.

In the event the support blade 33 is damaged for any reason whatsoever during the machining operation, it will be seen that in the preferred form of the invention above discussed wherein the same is made removable, that this support blade 33 can be easily removed by merely backing off the screw members that are received in apertures 34b, 34b with the result that the blade can be easily removed and a new blade simply and accurately repositioned within the slot 32 that is provided in the bit-supporting member 30. v

The modified form of the invention shown in Figures 6 and 7 of the invention is substantially identical with that described in connection with Figures 1 to S'hereof, and, accordingly, where indicated, like numerals designate like parts.

In this preferred form of the invention, however, a modified cutting bit is utilized that includes a carbide portion 81, having a cutting edge 81a, with the carbide cutting portion 81 being longitudinally abutted as at 82 to a shank portion indicated by the numeral 83. As before, this shank portion 83 has a threaded end extension 84 about which may be received a nut 85 for determining the height of the cuttings of edge 81a. In view of the fact that this modified form of the invention contemplates the elimination of the clamping block 60, the shank portion 83 further includes a central slot 86 having a counter-sunk shoulder slot 87 against which may be abutted a head 88a of a bolt 88 that is received in tapped aperture 89 provided in the end of the blade support 33. In this manner, the head 88a of a bolt 88, acting against shoulder 87, as shown best in Figure 7, will retain the overall cutting bit 80 with respect to the front edge portion of the support blade 33.

In useor operation of this modified form of the invention as shown in Figures 6 and 7, the component parts are assembled exactly as before with the exception that the bolt 88 is threaded into the aperture 89 in support blade 33 so as to hold the cutting bit 80 against the frontal edge portion thereof. With the device positioned as just described, the combined cutofi and chamfering operation may be eifectuated in the manner above described.

provided a newv and novelrtype;ofjjeoinbination cut-off and .chamferingttooll that; is capable of being'used .in a

multitude. of machining roperations It has further been shown howjthei relative adjustment ,that is possible be- Ytweenjthe cutting bit andthe phamferingt bit permits the 'useflof this combinedltool, on severalgdifierenbsiz es of bar stock in view of the fact that: the distance between ar -arse Itwil1 be seen fromjthe foregoingjthat thei ehastbeen the. charnfering; bit and cutting bit can be regulated radially of the cutting, pointjofj contact between the cutting bit 40 and the rotating work.

in this manner thecharrifering-tool can be adjusted so as to come into action. after the cutting. bit has-,passedthrough a predetermined, amount of'the rotating work,, and in this manner, any desired size and amount of ,charnfering can be provided bymer'ely adjusting the threaded bolt 2?.

His also. believedhimportant to note thatjthe support blade of this invention could be copper-plated so as to V achieve a rapid dissipation of heat in the critical cutting area. Particular reference is also to be noted with respect to the structure. ofthe cutting tool' per se that is employed in this invention. It has, been-shown in the preceding paragraphsrhow 'the'use of such a cuttingtool having-V independent adjustment means carried by the same, permitsa pre-setting of the overall effective length of this. cutting, bit with the result that the same can be easily removed. for grinding and then subsequently replaced Without. affecting in any way the. critical cutting height of thecutting edge thereof.

v While a-detailed description of the invention has been made'in accordance with the requirements of the patent statutes,.it is. to be understood that the invention is not to be so limited,-and, accordingly, modifications of the invention may be resorted to without departing from the spirit'hereof orthe'scope of the appended claims.

This application is a continuation, in part, of copending application Serial Number 441,305, filed July 6, 1954,

and now United States Patent-2,737,205; is also a continuation, inrpart, of copending application Serial Number 505,488, filedjMay- 2, 1945, by Raymond E, 'Novkov, and is a divisional application of copending application SerialNumber 592 A36, filedJune 19,; 1956', 'by Raymond What is claimed is:

" I A combination; cut-off and charnfering tool; of the character described, comprising; a tool body having for- :ward: and top edge surfaces; a bit support, releasably secured to said toolbody and having a bit-receiving surface disposed inv substanftiallyparallel relationship with said t opedgeg a support blade releasably' secured with respect to said tool body and said1bit, support and having 7 abit-receiving edge portion disposed'forwardly of said forward edge of said tool body; afirst bit received against bit-receiving surface of said bit support; a secondbit received against said bit-receiving edge portion of said support bladepmeans for releasably retaining said bit in position on said bit support and said support blade; and means for adjusting said bits relatively of. each other; saidbits having their cutting edges disposed in diiferent planes of cut.

2. A combination cut-off and chamfering tool of the characterdescribed, comprising; a tool body having forward and top; edge surfaces; a bit support, releasably secured to said tool body and having a bit-receiving suri face disposed in substantially parallel relationship-with saidrtop, edge; a support bladereleasably secured with respect .to said tool body and said'bit support and having said rbits being elongate and ei l su rl f isp e w t r pect q acho h ror v A T evi 9 l m r he c a acte ze y e fact that onesaid bitjisa cut-off bit whilethe .othercbit is acharnfering bit. V i t 4. A. combination cut-off andgchamfering tool of the character described, comprising; a tool 110 havingforward and top edge surfaces; a bit support, releasably securedto said tool body and having atbitr-receiving sur- 'facedisposed in substantially parallel relationship with said top edge; atsupportblade releasably secured with respect to's'aid tool body, and said bit support and having a. bit-receiving edge portion disposed forwardly of said forward edge of said tool body; ajfirst bit received against bit-receiving'surface ofisaid bit support; a second bit received against said bit-receiving. edge portion of said support blade; and means for retaining said bits against said bit-receiving surface and edge portions; lsaid retaining means including a clampingblockrcarried'by said tool body and having an edge receivedagain st said first bit, said bit being disposed at different angles. to each other 7 and having their cutting edges disposed in different planes.

5. A combination cut-off and chamfering tooltof. the character described, comprising; a tool'body havingcfo'r- Ward and top edge surfaces; a bit support, releasabl y secured to said tool body and having a bit-receiving surface disposed in substantially parallel relationship with said top edge; a' support blade releasably secured with respectsto said tool body and said bit support and having a bit-receiving edge portion disposedv forwardly of said forward edge of said tool body; a first bit received against bit-receiving surface of. said bit support; a second bit received against said bit-receiving edge portion of said support blade; and means for retaining said bits against said bit-receiving surface and edge portions; said retaining means including a clamping block carriedby said tool body and having. an edge received against said firstbit; and a second clamping block carried by'said bit support andhaving anledgereceived against saidjsecond bit'said bit being disposed at difierent angles to each'. other and having their cutting edges disposed in different planes. 6. The device of claim 4 furthencharacterizedby the fact that said support blade provided" with a tapped I aperture on its forward' bit receivihg edge-and said'lsecond a bit-receiving edge portion. disposed forwardly ofsaid forward edge of said'tool body; a first bit received against bit-receiving surface of. said bit support; a second bit abit-receivin gedge portiondispo'sedforwardly'of said forwardedge of said toolbod'y; a1 first bit received against received against said bit-receiving edge portion'fof said f support'blade; means fonreleasablyretainingsaid bit in position on said'bit support andsaidsupport blade; and,

means for adjusting said bits relatively of each other;

bit-receiving surfaceof said bit support; a second 'bit 7 received against said bit-receiving edge portion of said support blade; means for releasably retaining said bit in position on said bit support and said support blade; and means for adjusting said bits relatively, of each other; said means including,adjustment means for .shiftingvsaid first bit relatively of'said bit rec'eiving surface of" said bit support said bit being-disposed at different angles to each other and having their cutting edges disposed in different planes.

8 1A combination cut-off and, charnferingitoolfof the character described; comprising; a :toolflbojdy'having forward and/top edge surface's; a bit support; releasably secured-to said toolbodyf'and having a bit-receiving surface disposed in' substantiallyparalll relationship'with J said top'edge; a support blade releasablysecured' with respect to said tool body'and saidbitsupportand having a' b'it-rec'eiving edge portion disposed forwardly'bfsa'id forward edge of said tool body; a first bit received against bit-receiving surface of said bit support; a second bit received against said bit-receiving edge portion of said support blade; means for releasably retaining said bit in position on said bit support and said support blade; and means for adjusting said bits relatively of each other; said means including adjustment means for shifting said first bit relatively of said bit-receiving surface of said bit support; said adjustment means including a threaded bolt carried by said body and having its free end received against one end of said first bit said bit being disposed at difierent angles to each other and having their cutting edges disposed in different planes.

9. A combination cut-off and chamfering tool of the character described, comprising; a tool body having forward and top edge surfaces; a bit support, releasably secured to said tool body and having a bit-receiving surface disposed in substantially parallel relationship with said top edge; a support blade releasably secured with respect to said tool body and said bit support and having a bit-receiving edge portion disposed forwardly of said forward edge of said tool body; a first bit received against bit-receiving surface of said bit support; a second bit received against said bit-receiving edge portion of said support blade; means for releasably retaining said bit in position on said bit support and said support blade; and means for adjusting said bits relatively of each other; said means including adjustment means for shifting said second bit relatively of said bitreceiving edge of said support blade said bit being disposed at diflerent angles to each other and having their cutting edges disposed in different planes.

References Cited in the file of this patent UNITED STATES PATENTS 1,096,977 White May 19, 1914 1,223,438 Spencer Apr. 24, 1917 1,815,518 Luers July 21, 1931 1,919,738 Melling July 25, 1933 2,402,650 Mafiia June 25, 1946 FOREIGN PATENTS 144,902 Germany May 3, 1901 877,399 Germany May 21, 1953 

